Field of the Invention
The present invention relates to an acoustic panel which has the ability to absorb sound waves.
Spaces within buildings can be noisy. Soft furnishings are usually used within homes which help to absorb sound waves. In areas where there are insufficient soft furnishings, airborne sound waves reflect from walls and floors. This can become a problem in large, open spaces where soft furnishings are minimal, such as in open-plan offices, hospitals, and schools. The presence of large numbers of people can exacerbate the problem.
Noise can be defined as an unwanted sound. In the workplace, noise is a sound which interferes with normal activities, and can be extremely annoying or disruptive, reducing efficiency or preventing effective communication.
Sound waves are formed by waves of pressure that propagate through a compressible media, such as air. Waves can be reflected, refracted, or attenuated by the material through which they are travelling. Whether a noise is disturbing depends on two main factors: the frequency of the sound wave; and the pressure at which it reaches the ear (measured in decibels).
Generally, the levels of noise in office areas are below levels which pose a risk to hearing. Human hearing is not equally sensitive at all frequencies; although sensitivity is quite good in the range of 1 kHz to 4 kHz. Maximum sensitivity is usually around 3 kHz for people with normal hearing. The noise that is generated by conversation tends to have an audio frequency of between approximately 200 Hz and 8.2 kHz, but because of the limitations on hearing sensitivity, the range of interest for noise reduction is between about 500 Hz to about 8 kHz. White noise is generally considered to be less disturbing, and has the sound energy uniformly spread over a range of frequencies.
Noise can be generated internally, by people and equipment (telephones, photocopiers, printers, lifts, air conditioning, etc.) within a building. External noise can also enter a building, examples of which include road, air, and rail traffic as well as general industrial noise. Environmental noise can affect a person's performance of tasks such as reading and writing. Noise that prevents a person from understanding an instruction or a warning signal may also be a risk to safety. Generally, in an office environment, some privacy during conversations is required, and excessive noise levels can disrupt communication. In an environment such as a hospital, unwanted noise can affect a patient's sleep and comfort, and it is clearly desirable to reduce noise as much as possible.
A normal conversation between two people takes place at about 60 decibels. Often, background office noise, including distant conversations, reaches about 45-55 decibels. When workers are placed close together or in rooms with many people talking at the same time, decibel levels can rise to 70 or higher. A person sitting at a distance of 2 meters from a ringing telephone can be exposed to 70 decibels. If there is a lot of background noise, people will raise their voices to be heard, which further exacerbates the problem. Studies have shown that continuous exposure to noise levels over 60 decibels can affect a person's attention span, and may even increase stress levels.
Where noise is a potential issue, sound absorbent materials can be used, which include the use of insulating floor coverings, wall panels, ceiling panels, and acoustic dividing screens. Any materials used to assist with the absorption of sound need to comply with local fire safety regulations.
One method of reducing or controlling the noise level in this type of space is to use an acoustic or sound absorbing panel which is designed to absorb the sound within a room and to help reduce the amount of reverberation or echo within the space. The acoustic panel may take the form of a barrier, partition, or screen, and may form a dividing wall or may be fixed to a surface (such as a wall).
In addition to room dividers, sound absorbing panels are often fitted to walls in indoor spaces. This mimics the effect that soft furnishings would normally have. In certain environments (e.g. an office or a hospital), traditional soft furnishings are not appropriate and sound absorbing wall panels can provide a suitable alternative, even where space is limited. Conventionally, sound absorbing panels or dividing screens are formed from a plywood substrate covered in a layer of soft foam (also known as sheet foam), optionally further covered by a layer of fabric.
The subject matter discussed in this background of the invention section should not be assumed to be prior art merely as a result of its mention in the background of the invention section. Similarly, a problem mentioned in the background of the invention section or associated with the subject matter of the background of the invention section should not be assumed to have been previously recognized in the prior art. The subject matter in the background of the invention section merely represents different approaches, which in and of themselves may also be inventions.